The present invention relates to an improvement made to installations permitting the rapid cooling, and even freezing (or conversely heating), of various products, in particular of liquids such as drinks stored in bottles. In the description which follows, the invention will be described in the case of the treatment of liquids stored in bottles, but it is clear that no limitation is implied and that the installation according to the invention could be used for products stored in other forms (for example in the form of bags, metal boxes or cartons), or even for solid products.
In the field of the rapid cooling of various products, it is well known that best results are obtained by immersing the products to be cooled directly in the medium, for example directly in a very cold brine or melting ice, as is disclosed, in particular, in WO-A-88 03251 (corresponding to U.S. Pat. No. 4,920,763) or U.S. Pat. No. 2,422,350.
Although such a technique gives satisfactory results, it is clear that the contact between the product and the cooling medium has disadvantages, in particular in the case of foodstuffs. As a result, it was proposed a long time ago to envelop the product to be cooled with a thin protective film. All that remains to be said about this proposal is that, even with such a protection, in particular when the cooling fluid is a liquid, such a solution is not entirely satisfactory.
In order to obtain a rapid cooling, it was also proposed a long time ago, in particular in patent U.S. Pat. No. 2,061,427, to use chilling units comprising pockets (or the like) which descend into the chilling fluid and which are intended to contain bottles enclosing the liquid to be cooled. Such units have the advantage of being able to effect a rapid cooling of the bottles and of preventing the fluid from making their surface wet. In order to obtain a good efficiency, it is, however, necessary to have a good contact between the surface of the bottles and the envelope, which therefore entails either always using the same bottles for an envelope of given shape or, as described in the abovementioned document, having an extensible envelope (made from rubber) of a relatively complex structure since, in order to have good heat exchange, this entails the provision of metal inserts. Furthermore, even with such an extensible envelope, it is clear that the range of products which can be treated is limited, and that the envelope will not be applied correctly to the surface of an object having a shape other than cylindrical. Even though such an envelope can be expanded by virtue of the extensibility of the material of which it is composed, nevertheless it will not be applied against the surface of elements which have dimensions less than its nominal diameter. Lastly, the upper part of the bottle is not in contact with the wall of the envelope and it may be awkward to place and remove it since it must be introduced "by force" if it has a diameter corresponding substantially to the diameter of the envelope, whereas in the case of small bottles, as mentioned above, the envelope will not be applied against the periphery and, in addition, this will entail the placing and removal of the bottle by hand by thrusting one's hand into the envelope.
Not only does the invention make it possible to overcome the abovementioned problems but it also makes it possible to overcome a problem which has not been posed or overcome hitherto, which is that of being able to produce a unit permitting a programed period of heat exchange and not requiring any monitoring on the part of the user.